Comminutor for solids carried in flowing liquids

ABSTRACT

A comminutor for solid materials carried by a flowing liquid includes a sieve drum formed of axially spaced rings connected together. A comb unit is mounted adjacent to the drum and has a plurality of teeth which extend into the spaces between the rings so as to remove matter clogging the sieve slots. Axially extending grooves are formed in the periphery of the drum and carry a series of aligned fitted cutter pieces whose outwardly directed faces lie in a common plane which is radially inward of the outermost periphery of the drum. The drum cutter pieces together have an axially extending cutting edge which is exposed in the spaces between the rings. At least one piece of each cutter unit has a tooth which extends radially beyond the drum periphery. The cutter unit teeth and cutting edges coact with the cutting edges of the comb unit during rotation.

United States Patent 1.999,l49 4/1935 Durdin 210/174 2.267.088 12/1941 Durdin 210/174 X 2,336,069 12/1943 Chase .i ZlO/l74 Primary Examiner- Robert C. Riordon Assistant Examiner-Gary L. Smith Attorney-Spencer and Kaye ABSTRACT: A comminutor for solid materials carried by a flowing liquid includes a sieve drum formed of axially spaced rings connected together. A comb unit is mounted adjacent to the drum and has a plurality of teeth which extend into the spaces between the rings so as to remove matter clogging the sieve slots. Axially extending grooves are formed in the periphery of the drum and carry a series of aligned fitted cutter pieces whose outwardly directed faces lie in a common plane which is radially inward of the outermost periphery of the drum. The drum cutter pieces together have an axially extending cutting edge which is exposed in the spaces between the rings. At least one piece of each cutter unit has a tooth which extends radially beyond the drum periphery. The cutter unit teeth and cutting edges coact with the cutting edges ofthe comb unit during rotation.

PATENTEDJUNI SIS?! 35845743 SHEET 2 1F 2 lnwmam- Herbert Dinges /af a. BY

ATTORNEYS.

COMMINUTOR FOR sou s CARRIED IN FLOWING mourns BACKGROUND OF THE INVENTION This invention relates to comminutors for solid materials carried by a flowing liquid, and more particularly to such a comminutor having a sieve drum formed of axially spaced rings and having stationary cutting teeth mounted to engage within the slots between adjacent rings.

Such comminutors are well known and are described for example in U.S. Pat. No. 1,948,125 to C. H. Nordell, reissued as Re. 22,199. In this device the comminution of solid matter contained in sewage is accomplished by the interaction ofstationary comb teeth which protrude between the sieve drum rings and which engage with cutting teeth carried by the sieve drum. Individual cutting teeth are secured within grooves in individual sieve drum rings with threaded fasteners. With this device solid matter, particularly flat pieces such as leaves and textile shreds which are washed against the sieve drum are continuously lifted off by the comb teeth and comminuted by the coacting cutter and comb teeth. As a result clogging of the sieve slots is avoided.

U.S. Pat. No. 2,322,922 issued to C. W. Chase discloses a comminutor for solids carried in a flowing liquid. A sieve drum having circumferentially extending slots is provided. A cutting edge is fixed to the drums outer periphery and protrudes radially above it. This cutting edge engages with stationary comb teeth mounted to one side of the drum. The drum cutting edge'is formed in steps, each of which is angularly offset about the drum periphery. The fixed comb is also angularly offset relative to the drum periphery. Accordingly as the drum rotates the point of contact between the drum cutting edge and the stationary comb moves in an axially direction relative to the drum. Large pieces are therefore comminuted with an action somewhat like a pair of scissors in that the cutting point moves along the length of the cutting edge. This avoids the shocks which would result on the sieve drum bearings ifa cutting edge and teeth came together simultaneously along a full axial line.

However, continuous stripping of flat material such as leaves which is sucked against the sieve slots is not possible in this device since the cutting edge on the drum is raised radially above the drum periphery. Such thin but light weight pieces which are particularly likely to pass beneath the comb of this device often have a large area and accordingly clog large regions of the slots and cut offmuch flow area for liquid.

Canadian Pat. No. 733,242 to C. H. Nordell discloses a comminution device for use in sewers including a sieve drum formed of spaced rings. Cutters are mounted in recesses in the sieve drum and these engage with a stationary comb unit mounted to one side ofthe drum. The cutter unit has a cutting edge which is aligned with the drum periphery and teeth which extend beyond the drum periphery. The comb unit teeth are unable to extend between the sieve rings so as to clear the slots therebetween. Furthermore, the cutter in each recess is a unit, and in case of wear or breakage of one of the teeth the entire unit must be replaced.

Since effective prevention of clogging is of major importance in sewage comminutors the type of unit as shown in the first described U.S. Pat. No. 1,948,125 in which comb teeth fit between the slots is preferred by many users.

Wear and breakage of comb and cutter teeth and cutting edges is an inevitable part of the operation of these comminuting devices. Many existing devices require excessive operating and maintenance expense because replacement of such parts is awkward and time consuming and the parts which must be replaced are expensive and do not have a long operating life. Furthermore, special tools must often be used during replacement operations.

SUMMARY OF THE INVENTION Among the objects of the present invention is the provision of a comminutor for solid materials contained in flowing liquids, which has means for continually stripping off large flat pieces which are sucked against the sieve drum periphery, and in which solid matters are efficiently comminuted.

A further object of the invention is the provision of such a device in which the cutting teeth comb can be easily replaced in case of wear and without the use of special tools.

A further object of the invention is the provision of such a device in which the occurrence of sudden stresses on the drum during rotation as a result of a large number of coacting cutting edges coming simultaneously into engagement with each other during drum rotation is minimized.

A still further object of the invention is the provision of an arrangement in which the cutting unit on the drum and the comb unit lend themselves to use with drums ofdifferent sizes.

Briefly stated these and other objects of the invention are achieved by the provision of a comminutor including a sieve drum formed of a plurality of axially spaced-apart rings connected together by circumferentially distributed axially extending connectors joining the rings and in which cutter units are arranged in grooves formed in the drum periphery in the region of the axial connectors. Each cutter is formed of a series of aligned, fitted pieces, whose outwardly directed faces are flush and lie in a common plane which itself is radially inward of the outermost periphery of the drum, except that at least one piece of each cutter unit has a tooth which extends radially beyond the outermost periphery of the drum. A comb unit is fixed with respect to the rotating drum and has a plurality of teeth which extend into the spaces between the rings and has cutting edges which, during rotation of the drum, coact with the cutting edges of the said cutter unit to thereby comminute solid particles.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a side view of a comminutor according to the present invention, the comminutor portions being shown along a diametral section taken on the line 1-1 of FIG. 2.

FIG. 2 is a sectional view of the comminutor of the present invention taken along the line 11-11 of FIG. 1.

FIG. 3 is a view of the circumference of the drum of the comminutor of FIG. 1 as it would appear if it were unrolled and shown in a single plane.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings a comminutor 1 according to the present invention includes a rotating sieve drum 2 and a comb device 3. The sieve drum 2 is a cast body formed of individual rings 4 which are uniformly spaced from each other in an axial direction. The rings 4 are connected by supporting members 5 which extend parallel to the drum axis.

In the region of the support members 5 the drum 2 is formed with recesses 6 which extend radially into the body of the drum. Within the recesses fitted pieces 7 and 7' of two distinct types form a cutting unit 8. Cutting unit 8 extends along the entire axial length of the drum. The pieces 7 and 7' are generally similar except that pieces 7 have teeth 9 which extend radially beyond the drum periphery. Each piece 7 has a cutting face 7a which is so formed that all cutting faces 7a together of a single cutting unit 8 form a common cutting surface which occupies a plane which is flush and is radially inward of the outermost periphery of the drum. The two opposite edges of these faces 7a form cutting edges. The pieces have end surfaces which engage and support each other when they are fastened together to form a cutting unit 8.

The comb unit 3 includes a comb support 10 which is part of a housing 11 within which the sieve drum is mounted for rotation. A comb unit 12 is mounted on comb support 10. The comb unit 12 is formed ofa plurality of individual comb pieces which are axially aligned in a row and are similar to the pieces 7,7 forming the drum cutter unit 8. Teeth M and 16 extend from opposite sides of the comb unit. As illustrated in the drawings teeth 16 are positioned to coact with the teeth 9 of the drum cutter unit 8. Teeth 16 have cutting edges 16a and 1612 on their opposite sides. Cutting edges 16a are illustrated as cooperating with teeth 9 in FIG. 2. When cutting edge 16a becomes too worn to efficiently comminute pieces the comb unit 12 can be reversed so as to bring the cutting edge 1612 into cooperation with the teeth 9. When this cutting edge also becomes worn the unit can be rotated to bring the teeth 14 into cooperation with the teeth 9 and each of the cutting edges on opposite sides of teeth 14 can be successively used. In this way the cutting unit can be used four times before it needs to be replaced. The individual pieces forming the cutting unit 12 are so dimensioned that the height ofone piece corresponds to an integral number ofthe height ofcutting pieces 7 and 7.

if a sieve drum 2 of a smaller diameter than that illustrated in the drawings were used with the same housing either a comb piece 12 of different size, or additional comb pieces might be used to form the comb unit so that the total comb unit would have greater height. By providing sieve drums which vary in diameter by an amount equal to the height of comb pieces or cutting pieces 7, 7', cutting pieces 7 and 7 can be used without change no matter what size sieve drum is used. Recesses 6 of the same dimensions are provided on all sieve drums so as to permit this substitution.

In use sewage containing floating matter and solid wastes enters the housing ll through opening 13 which is located radially outward from the drum circumference. The fluid flows through the slots between the individual rings 4 and leaves the housing through an opening which is positioned axially through the drum.

7 During the passage of the sewage solids which cannot freely pass through the sieve slots due to their size are washed onto the sieve drum 2 and held there by pressure of the flowing liquid. The rotating sieve drum carries these pieces until they are lifted off by the comb. As they are lifted off, they are comminuted by the interaction of the stationary and rotating comminuting elements consisting of teeth 9, and the cutting edges ofcutter 8 and comb 12.

Due to the above-described construction of the comminutor l the sides of the comb teeth 16 continuously reach between the sides of the rings 4. The perpendicular cutting edges ofthe teeth 16 work, when in appropriate position of the sieve drum 2, against the free cutting edges of the faces 7a of the modules 7 and 7'. As previously mentioned, these faces are located radially inward of the drum periphery. Accordingly, any pieces clogging the sieve slots are continuously stripped from the sides of the comb teeth by the cooperation with the sides of the rings 4. This comminution process is augmented by the interaction of the radially extending cutting edges of the comb teeth 16 with the cutting edge of the teeth 9.

Particularly coarse pieces having a firmer consistency which become jammed in the slots are removed when the teeth 9 engage into the space between the comb teeth 16 during rotation of the sieve drum 2. In this matter such pieces are held by the comb ledge 12 and by comb teeth 16 and are thus subjected to the effects of teeth 9 so they are torn up at spaces between teeth 16. Due to the flow path produced by the construction of the sieve drum and by the configuration of housing 11, the comminutor solids flow through the sieve slots together with the flow ofliquid.

ln order to advantageously influence the comminution as well as the flow conditions, the rings 4 have a cross section which is smaller in regions which are radially closer to the axis ofthe sieve drum.

The cutter units 8 formed by pieces 7 and 7 have their outer surfaces disposed behind the sieve drum periphery by the width of the parallel side surfaces of rings 4.

in order to prevent too much strain caused by a number of cutting teeth 9 coming into engagement with comb teeth 16 at the same time each cutting unit 8 can be formed by alternating pieces 7 and 7'. Desirably, circumferentially adjacent cutting units 8 will be positioned so that the teeth 9 are offset from one another in the manner illustrated in FIG. 3 which shows the circumference of the drum as it would appear ifit were unrolled so as to occupy a single plane. Since the teeth 9 and 16 comminute pieces which have too firm a consistency to be comminuted by the engagement of the teeth between the individual drum rings 4, greater stresses can be expected to be created under these conditions;

A particular advantage of the present invention is that worn teeth 9 may be individually exchanged from the outside. This creates extremely favorable operating and maintenance conditions, particularly in view of the fact that the comb units 12 have four successively usable cutting edges.

The individual cutting pieces 7 and 7' of the drum cutter 8 support one another and have aligned frontal faces when assembled which form a closed cutting unit having two cutting edges. Moreover, the interaction of the sides of the comb teeth with the sides of the individual drum rings 4 continuously keeps the sieve drum slots free of clogging by solid pieces which might otherwise impede liquid flow.

A further advantage resides in the uniform stress on the sieve drum during the comminution process which results from the ability to vary the position of the cutting teeth. The drum cutter unit has two cutting edges which are perpendicular to each other and which engage with corresponding perpendicularly positioned cutting edges of the comb teeth.

The sieve ring sides are always overlapped by the sides of the comb teeth so that even the thinnest pieces will be continuously stripped off.

Known devices have been able to achieve individual ones of these advantages. But these advantages have been accompanied by considerable drawbacks which prevented the combination of all of these advantageous features into a single structure. It will be apparent that the present device makes possible the achievement of improved comminuting action, and the prevention of clogging, and provides a device which can be easily maintained, and the expense of replacement of parts due to wear is minimized.

It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.

Iclaim:

l. A comminutor for solid materials carried by a flowing liquid, comprising, in combination:

a. support means;

b. a sieve unit rotatably mounted on said support means,

said unit including 1. a gridlike drum composed of axially spaced-apart rings and circumferentially distributed, axially extending connectors joining said rings, said drum having, in the regions of said axial connectors, axially extending grooves, and a plurality of cutters arranged in the respective grooves, each cutter being composed of a series of aligned, fitted pieces whose outwardly directed faces are flush and lie in a common plane which itself is radially inward of the outermost periphery of said drum, said pieces having axially extending cutting edges which are exposed in the spaces between said rings, and at least one piece of each cutter having a tooth which extends radially beyond the outermost periphery of said drum; and

c. a comb unit mounted on said support means and having a plurality of teeth which extend into the spaces between said rings and having cutting edges which, during rotation of said drum, coact with said cutting edges ofsaid pieces.

2. The combination of claim 1 wherein each cutter is composed of two types of pieces, each piece ofone type having an integral cutting tooth formed thereon.

3. The combination of claim 2 wherein the pieces of each type have the same dimensions, except for said tooth.

4. The combination defined in claim 2 wherein each of said drum cutter pieces has end surfaces which engage and support each other when said pieces are fastened together to form a cutter unit.

5. The combination of claim 1 wherein said comb unit includes a piece having teeth extending outwardly therefrom.

6. The combination defined in claim 1 wherein said comb unit includes a piece having teeth extending therefrom in two different directions, and means for mounting said piece on the support in either of two positions, in one ofwhich the teeth extending in one direction coact with said drum cutters, and in the other of which the comb teeth extending in the other direction coact with said drum cutters.

7. The combination defined in claim 5 wherein said comb unit is substantially planar and said teeth extend in opposite directions, and said mounting means for the comb unit is arranged so that said comb unit can be arranged in any of four different positions whereby the teeth extending in each direction may be arranged to engage with said drum teeth on either side so as to accommodate wear.

8. The combination defined in claim 1 wherein said comb unit and said drum cutters are made in sets in which the height of the comb unit teeth corresponds to the radial extent of the cutter drum teeth.

9. The combination defined in claim 1 wherein said comb unit includes a plurality of individual pieces, and means for securing said pieces together in a direction extending along the length of the comb unit.

10. The combination defined in claim 1 including threaded fastener means for securing said cutters within said drum grooves.

11. The combination defined in claim 1 wherein the teeth of the cutters arranged in one groove are positioned at a different axial position along the drum whereby stresses resulting from the cutting coaction of the drum cutter and the comb teeth do not occur at the same time during rotation of the drum. 

1. A comminutor for solid materials carried by a flowing liquid, comprising, in combination: a. support means; b. a sieve unit rotatably mounted on said support means, said unit including
 1. a gridlike drum composed of axially spaced-apart rings and circumferentially distributed, axially extending connectors joining said rings, said drum having, in the regions of said axial connectors, axially extending grooves, and
 2. a plurality of cutters arranged in the respective grooves, each cutter being composed of a series of aligned, fitted pieces whose outwardly directed faces are flush and lie in a common plane which itself is radially inward of the outermost periphery of said drum, said pieces having axially extending cutting edges which are exposed in the spaces between said rings, and at least one piece of each cutter having a tooth which extends radially beyond the outermost periphery of said drum; and c. a comb unit mounted on said support means and having a plurality of teeth which extend into the spaces between said rings and having cutting edges which, during rotation of said drum, coact with said cutting edges of said pieces.
 2. The combination of claim 1 wherein each cutter is composed of two types of pieces, each piece of one type having an integral cutting tooth formed thereon.
 2. a plurality of cutters arranged in the respective grooves, each cutter being composed of a series of aligned, fitted pieces whose outwardly directed faces are flush and lie in a common plane which itself is radially inward of the outermost periphery of said drum, said pieces having axially extending cutting edges which are exposed in the spaces between said rings, and at least one piece of each cutter having a tooth which extends radially beyond the outermost periphery of said drum; and c. a comb unit mounted on said support means and having a plurality of teeth which extend into the spaces between said rings and having cutting edges which, during rotation of said drum, coact with said cutting edges of said pieces.
 3. The combination of claim 2 wherein the pieces of each type have the same dimensions, except for said tooth.
 4. The combination defined in claim 2 wherein each of said drum cutter pieces has end surfaces which engage and support each other when said pieces are fastened together to form a cutter unit.
 5. The combination of claim 1 wherein said comb unit includes a piece having teeth extending outwardly therefrom.
 6. The combination defined in claim 1 wherein said comb unit includes a piece having teeth extending therefrom in two different directions, and means for mounting said piece on the support in either of two positions, in one of which the teeth extending in one direction coact with said drum cutters, and in the other of which the comb teeth extending in the other direction coact with said drum cutters.
 7. The combination defined in claim 5 wherein said comb unit is substantially planar and said teeth extend in opposite directions, and said mounting means for the comb unit is arranged so that said comb unit can be arranged in any of four different positions whereby the teeth extending in each direction may be arranged to engage with said drum teeth on either side so as to accommodate wear.
 8. The combination defined in claim 1 wherein said comb unit and said drum cutters are made in sets in which the height of the comb unit teeth corresponds to the radial extent of the cutter drum teeth.
 9. The combination defined in claim 1 wherein said comb unit includes a plurality of individual pieces, and means for securing said pieces together in a direction extending along the length of the comb unit.
 10. The combination defined in claim 1 including threaded fastener means for securing said cutters within said drum grooves.
 11. The combination defined in claim 1 wherein the teeth of the cutters arranged in one groove are positioned at a different axial position along the drum whereby stresses resulting from the cutting coaction of the drum cutter and the comb teeth do not occur at the same time during rotation of the drum. 